...and back on topic : I am currently hesitating between the Adriano Lolli and the Lensbaby. What pushes me towards the more expensive Lensbaby is that the Lolli, in the video on the website, seems to be not very smooth when turning the lens around, whereas the Lensbaby has a ball system that seems much better in that regard - what do you think after playing with the Lolli ?

I've just received my Lolli (COMA) adaptor and it seems similar in design to the Lensbaby with the ball arrangement - how loose it is when you turn it depends on how tight you set the lever. However, I believe the Lensbaby allows you to adjust the aperture on Nikon lenses with the manual aperture control (e.g. G series) whereas the COMA does not.